Does Detect Magic detect the effects of Rebuke Undead?

Question

If an undead creature is under a caster's control by Rebuke Undead (as applied to a weaker undead under the Control Undead threshold), would a casting of Detect Magic give any indication of that?

Answer 1

According to FAQ – yes.

Turning/rebuking undead is a supernatural ability.

Supernatural abilities are magical and go away in an antimagic field but are not subject to spell resistance, counterspells, or to being dispelled by dispel magic.

Unfortunately, the rules don´t say (as far as I know, at least), whether an effect created by a supernatural ability has a magical aura that can be detected by the spell detect magic. Also, the description of the spell only refers to spells and magic items.

In the FAQs I found this entry:

Can you use detect magic to detect supernatural effects? For example, can it detect a wildshaped druid? - Supernatural abilities are magical, and thus their effects would produce magical auras. Although the detect magic spell doesn’t have a line entry for supernatural effect, you can use the same line as “Magic item (caster level)”—a supernatural effect’s caster level is equal to the creature’s Hit Dice unless noted otherwise (MM 315).

Following this, detect magic would reveal a magic aura on an undead creature which is under the effect of a cleric´s turn/rebuke undead ability.

Answer 2

No one knows

There are several questions with unclear answers here that the ultimate answer depends on.

Can detect magic detect supernatural abilities?

As another answer notes, the FAQ says 'yes'. It, however, does not explain all the details necessary for such a ruling to work: for example, it does not explain how to calculate the school of a supernatural ability, nor on which creature(s) or object(s) the magical aura is present.

Detect Magic itself seem ambivalent on the issue, both noting "Presence or absence of magical auras" under the first round effects without qualifiers, yet also noting "Outsiders and elementals are not magical in themselves, but if they are summoned, the conjuration spell registers". Furthermore, the spell states "A magical aura lingers after its original source dissipates (in the case of a spell) or is destroyed (in the case of a magic item)".

In argument against the spell detecting supernatural abilities, there is the lack of support in the table for that, the fact that almost all outsiders and elementals have supernatural abilities (so one would mention that, rather than summoning spells), and the fact that lingering auras have rules for item and spell sources, but not for supernatural ability sources.

In argument for the spell detecting supernatural abilities, there is the way that the spell description seems to implicitly assume that items and spells are, like, somehow all of 'magic' and the generalization that detect magic, then, is probably supposed to detect that. There is also the weird consequence that if Su abilities don't register to detect magic that means that they don't have magical auras, which can be very counter-intuitive, particularly if such a ruling were extended to Sp abilities, which are technically also not spells. There's also the fact that the FAQ thinks this is the way it works or should work or something.

If the answer to this question is 'no', detect magic cannot detect the effects of rebuke undead. If yes, we need to address more questions.

What is rebuke undead's duration?

Again, this is not clear. We know that you can take an action and that afterwards effects may persist for a while. We do not know whether those effects are consequences of instantaneous-like magic or not. That is to say, if rebuke undead works like fireball, the effects are not magic even though the ability is. In that case, you could see the magic of a Cleric rebuking undead but not anything on an undead that had been rebuked-- there would be nothing to see in the second case.

Answer 3

I would say no yes (as the question is for commanded creatures, shame on me), but read the edit

Peregrin Took's answer covers really well the general rule on supernatural effects, and it applies to commanded undead (or any other creature) as you maintain a bond with those entities so you can order them for as long as you want, but a rebuked creature only cowers.

However, if you understand the effect as a long time effect, which could be dispelled (by RAW that only applies to turned creatures, not rebuked ones) you could detect some kind of aura from them.

Is like a fireball or an attack with a magic weapon, the damage is magical, but the burn/scar in your body isn't.

Edit: I want to emphasize that I do think that controlled creatures might emanate some kind of aura, but rebuked ones don't. Most spells have a duration specified because you can dispell the effect by magical means and/or some way to interact with the affected target, while Rebuke (and Destroy to be fair) is an instantaneous action with a consequence, like the Command spell when you issue the Drop command.

You give the subject a single command, which it obeys to the best of its ability at its earliest opportunity. You may select from the following options

Drop: On its turn, the subject drops whatever it is holding. It can’t pick up any dropped item until its next turn

As the sword being in the floor is a consequence of a spell and not the spell effect, you can't dispell the finished order to make the the sword return to its owner hand.

In fact, we could even argue about the descrption of turning/rebuking undead meaning that the affected creatures are simply "moved" in the same way a politician "moves" peopel with their speeches:

Turn or Rebuke Undead (Su): Any cleric, regardless of align-ment, has the power to affect undead creatures (such as skeletons, zombies, ghosts, and vampires) by channeling the power of his faith through his holy (or unholy) symbol

In which case none of the cleric's magical power is proyected to any creature, acting more like a megaphone to influence it's targets in the same way Eagle's Splendor buff a Diplomacy roll, but I'm not really set into this interpretation of the rule.